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【简答题】
B As many as 10 of the 17 kinds of penguins(企鹅)may be in danger of disappearing.The number of penguins has decreased by 30%since 1987. Penguins are black and white birds that live in the southern part of the world.They are common in South America,New Zealand,Australia and South Africa."Many live near cold waters.But some live near wa l l waters in Galapagos Islands.Penguins cannot fly,but they are fine swimmers.Penguins eat fish and krill. The warming of the earth is the cause of the decrease in penguin populations.The heating of the air has caused ocean waters to become warmer.Higher water temperatures have reduced the supply of fish and krill.Some years later these birds are completely unable to reproduce.Besides,many adult penguins die of hunger. Widespread fishing,exploration for oil and oil leaks also make penguins be in danger.Poisonous organisms in ocean water are another danger.Penguins also have their enemies,including wild dogs,sharks,seals and sea lions. News about penguins is not all bad.However,several years ago,oil leaking from a ship hurt 40%of the penguins in South Africa.The penguins became covered with oil.But thousands of people helped clean and treat the birds well.Then they returned the penguins to the wild.Now these South African penguins are reproducing in higher numbers than before the oil leaking.
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【单选题】刚体绕定轴转动时,以下四种说法,哪一个是正确的?
A.
当转角 j >0 时,角速度 w 为正
B.
当角速度 w >0 时,角加速度 e 为正
C.
当 w 与 e 同号时为加速转动,当 w 与 e 反号时为减速转动
D.
当 e >0 时为加速转动,当 e <0 时为减速转动
【单选题】Take a regular holiday away from home to relax yourself from the pressure of your work, even if you are living on a tight ______.
A.
certificate
B.
catalog
C.
budget
D.
commitment
【简答题】Momentum busters refer to ______ that will pr you from continuing to work.
【单选题】刚体绕定轴转动时,以下四种说法,哪一个是正确的?
A.
当ω与角加速度α同号时为加速转动,当ω与α反号时为减速转动
B.
当ω>0时为加速转动,当ω<0时为减速转动
C.
当ω>0时,角加速度α为正
D.
当转角φ>0时时,角速度 ω 为正
【单选题】静脉瓣膜袋由以下结构构成
A.
瓣叶、附着缘
B.
瓣叶、附着家、交会点
C.
瓣叶、附着缘、静脉壁
D.
瓣窦、附着缘、静脉壁
E.
瓣窦、附着缘、交会点
【单选题】静脉瓣膜袋由以下结构构成
A.
瓣叶、附着 缘
B.
瓣叶、附着缘、交会点
C.
瓣叶、附着缘、静脉壁
D.
瓣窦、附着缘、静脉壁
E.
瓣窦、附着缘、交会点
【单选题】刚体绕定轴转动时,以下四种说法,哪一个是正确的?( )
A.
当转角 时,角速度 为正;
B.
当角速度 时,角加速度 为正;
C.
当 与 同号时为加速转动,当 与 反号时为减速转动;
D.
当 时为加速转动,当 时为减速转动。
【单选题】It was impossible for you to avoid ______ if you both work in the same office.
A.
from being affected
B.
being affected
C.
affecting
D.
to be affected
【单选题】配送中心在所取定的选址点进行建设时,必须研究并判断选址的( )条件
A.
指导
B.
障碍
C.
衔接
D.
控制
【判断题】因为 H=Qp,而H是状态函数,所以热Q也是状态函数。
A.
正确
B.
错误
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